Bluetooth
This page is under construction, but aims to get you more familiar with Bluetooth and how the PineTime utilizes it
PineTime Bluetooth LE agreements
These are aimed for firmware developers primarily, and should describe how to design your firmware to be interoperable with the rest.
External references
Uncovering Privacy Leakage in BLE Network Traffic of Wearable Fitness Trackers - http://phpathak.com/files/hotmobile-fitness.pdf
Protecting Privacy of BLE Device Users - https://www.usenix.org/system/files/conference/usenixsecurity16/sec16_paper_fawaz.pdf
Bluetooth: With Low Energy Comes Low Security - https://www.usenix.org/conference/woot13/workshop-program/presentation/ryan
Introduction to Bluetooth Low Energy development - https://devzone.nordicsemi.com/nordic/short-range-guides/b/getting-started/posts/introduction-to-bluetooth-low-energy-and-ble-devel